Use these tools to advertise job openings and mine the social network for prospects.

Human resources departments and recruiters can use Facebook apps to post jobs inside the 800 million member social network or identify and track potential job candidates either directly or through employee referrals.

Here's a partial list of apps that have debuted in the past 18 months. For each, corporate customer numbers come from the developers, and Facebook user numbers come from Facebook. For more on Facebook recruiting apps, click here:

Name:BeKnown

Company: Monster Worldwide Inc.

Debuted: June 2011

Description: The consumer app lets job seekers create a private, LinkedIn-style professional network on top of their regular Facebook contacts, scan jobs that they might be interested in, or share job listings with Facebook friends. The app pulls listings from multiple Monster job boards for BeKnown users to scan without leaving Facebook.

Cost: Free for job seekers and companies

Users: 350,000 average monthly active Facebook users

Good to know: Now companies can create a profile page on BeKnown with career and other news, then link to it from a BeKnown Jobs Tab on their Facebook page.

Name:RecruiterConnect

Company: BranchOut

Debuted: October 2011

Description: Started in July 2010, BranchOut was the first and remains the largest professional networking app for Facebook, letting job seekers build a virtual network of business connections that's on top of Facebook's platform but not part of it. In October, BranchOut unveiled RecruiterConnect, a fee-based tool company recruiters can use to source candidates through employee referrals, build private talent networks and organize and share applicant profiles, folders, notes and reminders.

Good to know: Through a just-announced partnership, CareerBuilder.com will incorporate the BranchOut app into its job boards, starting with CareerRookie.com. Earlier this year, BranchOut hired a former Yahoo and Monster executive to oversee sales and recruiting industry product development. To date, the company raised $24 million in venture financing.

Description: Cornerstone's revamped cloud-based recruiting software suite will include a Facebook recruiting app. Recruiters can use the app to source candidates from existing employees or external prospects.

Description: Facebook members can use the Glassdoor app to look for jobs, research salaries or write public reviews of what it's like to work or interview with a particular company. Companies can use Glassdoor's Enhanced Employer Profile service to add news, job openings, photos or other data to their profile on Glassdoor's website and the information is automatically pushed to the app.

Good to know: If Glassdoor's crowdsourced-review concept sounds a lot like TripAdvisor, it's no coincidence. The travel site's CEO sits on Glassdoor's board.

Name:Work@

Company: CareerBuilder

Debuted: September 2010

Description: The employee referral app lets workers share open jobs at their companies with personal and professional contacts on Facebook. Recruiters can use built-in tracking tools to see who's sharing the most jobs and generating the most referrals.

Good to know: Work@ plugs into other vendors' applicant tracking systems to manage requisitions and applications, and produce reports.

Name:Work With Us

Company: Jobvite

Debuted: October 2011

Description: Previously, a company's employees used Jobvite's 2-year-old applicant tracking system or recruiting sourcing software to push information on job openings to their connections on Facebook or other social networks. Now, customers can access both of those hiring applications directly from Facebook using the new Jobvite Work With Us app. Companies can also use the app to add a jobs tab to their corporate Facebook page. Job hunters can use the app to apply for jobs by either uploading a résumé or using work history information from their Facebook profile.

Cost: Pricing for Jobvite Hire ATS software is based on the company's total employees, and for Jobvite Source recruiting software on number of users.

Users: Spotify, the popular online music-sharing service, is an early corporate customer; 6,000 average monthly active Facebook users

Good to know: Jobvite officials say 43 percent of employee social referral hires on their software platform come from Facebook.

Michelle V. Rafter is a Workforce Management contributing editor based in Portland, Oregon. To comment, emaileditors@workforce.com.